body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-image: url(../img/待.jpg);
  background-repeat: no-repeat;
  background-size: 100%;
}
.container {
  width: 600px;
  margin: 50px auto;
}
h1 {
  text-align: center;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  padding: 10px;
  border-bottom: 1px solid #ccc;
}
#taskInput {
width: 300px;
height: 50px;
margin-left: 30px;

}
button{
height: 50px;
width: 100px;
}
.priority-high {
  color: red;
  font-weight: bold;
}
.completed {
  text-decoration: line-through;
  opacity: 0.5;
}